The document discusses different speech styles or levels of language that depend on the communication context, including the people involved, location, and type of occasion. It identifies five main speech styles: intimate, casual, consultative, formal, and frozen. The intimate style is between close relationships and does not focus on grammar. The casual style is informal and uses slang. The consultative style is standard language between professionals. The formal style requires advance planning and is very structured. The frozen style uses traditional, unchanging language for ceremonies. Choosing the right speech style is important for effectively delivering and conveying messages depending on the situation.